The aim of this clinical study was to evaluate tooth color change after exposure to different whitening methods using several materials ( hydrogen peroxide 7.5%, carbamide peroxide22%- which gives 7.5%of hydrogen peroxide – carbamide peroxide 45% using its two methods of application .
20 subjects ( 240 upper and lower anterior teeth) were distributed into 4 groups ( 60 teeth were submitted to 45-min exposure of cp 22% daily for 14 days . 60 treated with 45-min daily of hp 7.5% for 14 days, 60 treated with 3 exposures of 45- min of cp 45%, 60 were submitted to combined treatment of one exposure to cp 45% and 45 min exposure daily to cp 22% for 7 days . instrumental color measurements were obtained from teeth before bleaching and 14 days after treatment using Vita easyshade compact . color change ΔE were calculated using this equation ∆E= [(∆L*)2 + (∆a*)2 + (∆b*)2]1/2 Data were analyzed using ANOVA test to study statistically differences among 4 groups, and t test to study differences between upper and lower jaw .
there was statistically significant difference among the four whitening groups at ( p=0.01), no differences at p=0.05 between HP 7.5%group & CP45% group, CP 22%group & CP 22%+ CP 45% group . Whereas HP 7.5%group & cp 45% group were more effective than cp45%+ cp 22%group & cp 22% group.
Within the limitations of this study, materials were arranged from the most effective to the less effective like this (fgm ( hp7.5%) ، (opalescence ( cp45%) ,opalescence ( cp45%) + % fgm( cp 22) ، fgm (cp 22%) . without statistically significant difference between upper and lower jaws for all studied groups.
Damascus University Journal.
2014.